Certain geminal bisphosphonic acid compounds, including their salts and esters, are effective against alveolar bone loss and unwanted tooth movement. Problems with such compounds include that the compounds are generally negatively charged molecules and not capable of penetrating oral tissue very readily. Although such drugs have been administered systemically, their rate of absorption is quite poor.
Iontophoresis is a technique for delivering ions into a person's tissue by placing a solution, or other medium containing the ion, in contact or close proximity with the tissue; the solution or medium containing the ions is typically carried by a first electrode pouch or receptacle. A second or dispersive electrode is placed against the tissue within some proximity of the first electrode. Ions are caused to migrate from the ion-carrying medium through the tissue by the application of an electrical potential or voltage of the appropriate polarity to the two electrodes. A controlled current is established by providing a sufficient voltage differential between the first and second electrodes, and placing a limiting resistance or other current-limiting device elsewhere in the circuit.
Applicant has surprisingly found that when administered via iontophoresis, certain bisphosphonate compounds not only inhibit alveolar bone resorption associated with periodontal disease and stabilize tooth movement during orthodontic procedures, but they do so at low dosages. When administered via iontophoresis, the dosage amount may be low enough such that there is little or no systemic level of drug, but the dosage is nonetheless effective in providing a local benefit.